Fastening member

ABSTRACT

This invention relates to a fastening member for securing an element on a shaft. The fastening member is to be placed without radial play between the external cylindrical surface of the shaft and an interior cylindrical surface of a groove coaxial with the shaft and formed in the element. The fastening member comprises anchoring means preferably in the form of teeth defined by forming a plurality of recesses on the inner and outer peripheral surfaces of a frusto-conical metallic annulus. The anchoring means are capable of acting in a radial direction so as in use to secure the element both against rotation and against movement in an axial direction relative to the shaft.

[ Dec. 18, 1973 FASTENING MEMBER [76] Inventor: Roger Habert, 73 Avenuede la Republique, Epinay/Seine, France [22] Filed: Nov. 11, 1971 [21]Appl. No.: 197,670

[30] Foreign Application Priority Data Nov. 17, 1970 France 7041155 [51]Int. Cl. Fl6d 1/06 [58] Field of Search 287/52.04, 52.07, 287/52 R;151/41.74, l4 DW; 85/8.8, 36; 285/340 3,007,726 11/1961 Parkin 85/363,365,219 l/l968 Nicolaus... 285/340 2,989,327 6/1961 Hermanus 287/52 RPrimary Examiner-Andrew V. Kundrat Attorney-1-1olman & Stern [5 7ABSTRACT This invention relates to a fastening member for securing anelement on a shaft. The fastening member is to be placed without radialplay between the external cylindrical surface of the shaft and aninterior cylindrical surface of a groove coaxial with the shaft andformed in the element. The fastening member comprises anchoring meanspreferably in the form of teeth defined by forming a plurality ofrecesses on the inner and outer peripheral surfaces of a frusto-conicalmetallic annulus. The anchoring means are capable of acting in a radialdirection so as in use to secure the element both against rotation andagainst movement in an axial direction relative to the shaft.

2 Claims, 8 Drawing Figures FASTENING MEMBER BACKGROUND OF THE INVENTIONThe present invention relates to a fastening member for securing anelement rigidly on a shaft and more particularly for securing theelement both against rotation and against movement in an axial directionin relation to the shaft.

PRIOR ART It is known that an element can be fixed by means of radialclamping on a shaft using a frusto-conical washer, which has in itsinternal or external peripheral surface radial slits for increasing itselasticity. This washer is disposed practically without clearancebetween the cylindrical outer surface of the shaft and a cylindricalinner surface of a groove coaxial with the shaft which groove is made inthe element to be fixed on said shaft. An axial gripping effect isapplied to the washer so that it tends to become flat and so that itsouter diameter becomes greater at the same time as its inner diameterbecomes smaller. The axial clamping stress develops in this way agreater radial stress, and the latter causes the inner and outerperipheral surfaces of the washer to lie radially against thecylindrical outer surface of the shaft and the cylindrical inner surfaceof the groove of the element respectively, so as to immobilise thelatter in relation to the shaft by radial clamping.

In this previously known method of fixation, the washer is elasticallydeformed so that the axial clamping stress must be permanentlymaintained and can only be produced by adjoining an auxiliary clampingdevice to the washer such as a screw and nut which ensures that thewasher is clamped axially and thus causes the element to be secured onthe shaft by radial clamping. The radial slits formed in the washer onlyhave the function of increasing its elasticity and allow it to becomeflat to a certain extent. Moreover with a method of fixation such asthis it is not possible to transmit large torques for when these becomegreater than the frictional forces between the inner and outerperipheral surfaces of the washer and the cylindrical surfaces of theshaft and the groove of the element respectively, then the surfaceswhich are in contact will move in relatiori to each other.

OBJECT AND SUMMARY OF THE INVENTION The object of the invention isessentially to overcome the disadvantages of the fastening memberdescribed above, by doing away with the auxiliary clamping device.

In accordance with the present invention there is provided a fasteningmember for securing an element on a shaft, which fastening member is tobe placed without radial play between the external cylindrical surfaceof the shaft and an interior cylindrical surface of a groove coaxialwith said shaft and formed in the element, wherein the fastening membercomprises anchoring means capable of acting in a radial direction so asin use to secure the element both against rotation and against movementin an axial direction relative to the shaft.

Preferably, the fasteningmember comprises a frustoconical metallicannulus, wherein it is made of a metal which can be permanentlydeformed, and wherein it is formed with a plurality of recesses on itsinner and outer peripheral surfaces to define teeth which form saidanchoring means and which can anchor themselves radially in therespective cylindrical surfaces of the element and the shaft when thefastening member is placed between said cylindrical surfaces and afterit is subjected to a sufficient temporary axial pressure to permanentlydeform and thereby flatten it.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIGS. 1 and 2 are respectively a plan view and an axial cross-section ofa fastening member for securing an element on a shaft according to thepresent invention, the section of FIG. 2 being made along the line II-IIof FIG. 1,

FIG. 3 shows the element mounted on the shaft and before being securedon said shaft,

FIG. 4 is similar to FIG. 3, but showing the fastening member before itsecures the element on the shaft,

FIG. 5 shows an axial section of a type of mounting which can be used toplace the fastening member in position,

FIGS. 6 and 7 are views in cross-section and plan respectively of theelement secured rigidly on its shaft, and

FIG. 8 is a view on an enlarged scale of a detail of FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIGS. 1 and 2, thefastening member shown therein comprises a frusto-conical metallicannulus 1. The internal and external peripheral edges of this annulusare formed with a plurality of recesses 2 and 3 respectively which,spaced at regular intervals, define between them teeth 4 and 5respectively thereby forming anchoring means. Although as shown in FIG.1 the internal and external teeth 4 and 5 are radially aligned, it is tobe appreciated that this need not be so. Respective edges 6 and 7 of theteeth 4 and 5 are parallel to the geometrical axis YY of the annulus.

Thus, when an axial force is applied to the annulus l in a manner whichwill be described in detail hereinafter, the annulus 1 tends to becomeflat and the edges 6 and 7 adopt a position which is oblique in relationto the axis YY, so as to form sharp radial points with the flat surfacesof the annulus, as is shown more particularly in FIG. 8.

In FIG. 3 an element 8 is shown which is about to be fixed rigidly on ashaft 9 by the annulus l. A groove 10 is formed in the element 8coaxially with the shaft 9, of which the internal cylindrical surface10a has a diameter which is equal to the outer diameter of the annulus1, while the shaft has an outer diameter which is equal to the innerdiameter of the annulus.

As shown in FIG. 4, the annulus II is positioned in such a way that theouter surface of the annulus l is adjacent to the internal cylindricalsurface of the groove 10, the annulus tapering inwardly in an axialdirection away from the element b. In addition there is practically noradial play between the ring 8 and the cylindrical surface 10a of thegroove 10, nor between the ring and the cylindrical surface of the shaft9.

In order to carry out the actual securing operation a chuck 12 (see FIG.5) is mounted so that it is fixed to the shaft 9 in such a way that itsforward surface 13 is positioned following a plane corresponding to amounting reading of the element 8 on the shaft 9. This forward surface13 engages the narrow axial end of the frusto-conical annulus l.

A piston 14 is brought into contact with that axial end of the element 8remote from the annulus 1. An axial stress is thereafter applied to theelement 8 by the piston 14, and the element moves in the direction ofthe arrow F (FIG. Due to the movement of the element 8, the annulus 1 iscompressed and its outer diameter increases and at the same time as itsinner diameter is reduced.

Since the axial stress exerted on the annulus 1 develops a much largerradial stress, the external teeth 5 of the annulus penetrate intothe,cylindrical surface 10a of the groove 10 at the same time as theinternal teeth 4 penetrate into the cylindrical surface of the shaft 9at the level of the plain xx (FIG. 8). The annulus 1 must of course bemade of a harder metal than the materials constituting the elefment 8and the shaft 9.

Furthermore, the metal of which the annulus is made must be able to besubjected to permanent deformation and the axial compression stressexerted by the piston 14 is chosen in such a way that the constraintswhich it engenders in the annulus 1 are greater than the elasticitylimit of the inetal but smaller than its breaking limit, so that whenthe; compression stress exerted by the piston 14 ceases, the annulusremains noticeably flat.

In this way one can secure the element 8 rigidly on the shaft 9 as isshown in FlGS. 6 and 7. The element 8 cannot rotate nor move axially inrelation to the shaft 9. This method of secullng has numerousadvantages, in particular economical and technical advantages such asthe following the angular position and the axial position of the elementon the shaft can be finally adjusted at the moment of securing;

no intermediary clamping part or member is required;

with this method much larger torques can be transmitted than waspossible with previously known washers.

The invention is of course not limited to the embodiment of thefastening member which has been described above and which has beenchosen purely by way of example and is not at all limiting. Thus, therecesses 2 and 3 which define the teeth 4 and 5 respectively can be ofany other suitable shape, such as of V- shaped configuration and anynumber of them may be provided.

I claim:

1. A fastening member for securing an element on a shaft, whichfastening member can be placed without radial play between the externalcylindrical surface of the shaft and an interior cylindrical surface ofa groove coaxial with said shaft and formed in the element, wherein saidfastening member comprises a frustoconical, metallic, permanentlydeformable annulus of a material harder than the material constitutingthe element and shaft and of a predetermined limited elasticity, saidannulus having a plurality of recesses on its inner and outer peripheralsurfaces to define spaced teeth each having a single edge parallel tothe geometrical axis of the annulus and with the parallel edges on theinner periphery being formed by a series of intersecting arcuate cutoutportions which define said recesses on the inner periphery whereby saidteeth anchor themselves radially in the respective cylindrical surfacesof the element and the shaft when the fastening member is placed in usebetween said cylindrical surfaces and after the fastening member hasbeen subjected to a sufficient temporary axial pressure to permanentlydeform and thereby flatten it, so as to secure the element both againstrotation and against axial movement relative to the shaft.

2. An assembly comprising a shaft, an element surrounding the shaft andhaving a groove coaxial with the shaft, and a fastening member asclaimed in claim 1 for securing the element on the shaft, said annulusbeing mounted without radial play between the external peripheralsurface of the shaft and the interior cylindrical surface of the groove.

1. A fastening member for securing an element on a shaft, whichfastening member can be placed without radial play between the externalcylindrical surface of the shaft and an interior cylindrical surface ofa groove coaxial with said shaft and formed in the element, wherein saidfastening member comprises a frusto-conical, metallic, permanentlydeformable annulus of a material harder than the material constitutingthe element and shaft and of a predetermined limited elasticity, saidannulus having a plurality of recesses on its inner and outer peripheralsurfaces to define spaced teeth each having a single edge parallel tothe geometrical axis of the annulus and with the parallel edges on theinner periphery being formed by a series of intersecting arcuate cutoutportions which define said recesses on the inner periphery whereby saidteeth anchor themselves radially in the respective cylindrical surfacesof the element and the shaft when the fastening member is placed in usebetween said cylindrical surfaces and after the fastening member hasbeen subjected to a sufficient temporary axial pressure to permanentlydeform and thereby flatten it, so as to secure the element both againstrotation and against axial movement relative to the shaft.
 2. Anassembly comprising a shaft, an element surrounding the shaft and havinga groove coaxial with the shaft, and a fastening member as claimed inclaim 1 for securing the element on the shaft, said annulus beingmounted without radial play between the external peripheral surface ofthe shaft and the interior cylindrical surface of the groove.